The invention relates generally to a control device for an industrial truck, in particular the hitch of a towbar-guided industrial truck, with a circuit element for the generation of a multi-stage electrical control signal.
Control devices for industrial trucks are equipped with control elements for the actuation of the various functions of the industrial truck, such as operation of the truck or an associated lifting apparatus. Depending on the function to be controlled, the control elements have circuit elements for the generation of actuation/deactuation control signals in the form of multi-stage or stepless control signals. Multi-stage or stepless control signals are used in particular to control the speed of travel of the industrial truck or to control the speed of raising and lowering a load-carrying device.
Signal generators of the prior art for the generation of multi-stage control signals entail significant effort and expense in terms of design and construction and consist mostly of a plurality of mechanical and electrical components that are subject to wear. A signal generator of the prior art to be used on an industrial truck for the generation of a stepless control signal is described in DE-GM 94 17 201, for example. The circuit element described in that document is realized in the form of a membrane potentiometer and has a resistance track attached to a flexible pin, by means of which it is possible to generate a control signal which is proportional to the distance the control element is moved. The electrical and mechanical components of this signal generator of the prior art are complex and expensive to design and manufacture.
Therefore, it is an object of the invention to make available a control device with a simple, low-wear circuit element for the generation of a stepped control signal.